A) Stroke patients might benefit from virtual reality that increases the gain of patients' movements
B) Stroke patients might benefit from virtual reality that decreases the gain of patients' movements
C) Stroke patients might benefit from robots that assist or, in some cases, resist movements
D) All of the above

A) They show significantly higher timing variability in rhythmic tapping tasks than do typically developing children
B) They exhibit patterns of muscle timing that are less functionally suited to restoring balance than do typically developing children
C) They take longer to respond to release of the arm when it is initially held by a mechanical device than do typically developing children
D) They take longer to response to visual stimuli than do typically developing children

A) The research in economics showed that people are unable to optimize along classically expected lines, and the research on aiming showed the same thing
B) The research in economics showed that people are unable to optimize along classically expected lines, but the research on aiming showed that people can
C) The research in economics showed that people are able to optimize along classically expected lines, and the research on aiming showed the same thing
D) The research in economics showed that people are able to optimize along classically expected lines, but the research on aiming showed that people cannot